You create a view for every single table and the select clause has the schema name embedded.
How about using views to mask the schema name. you can only have one instance of a customer or client or orders or whatever. I think Public synonyms are okay as long as you use them judiciously and are fully aware of the implications - i.e. Talk about maintenance - every time you add or drop an object you have to maintain private synonyms for every single user. Private synonyms work but what if there are hundreds of users - you don't want to create private synonyms for that many users. What if you have an application that needs tables from multiple schema? SET CURRENT_SCHEMA is not going to help in this case because you are selecting from many schema. But just like triggers.you better be sure you really need them if you want to use them. So just because someone liked synonyms, the server performs far worse than possible with the given hardware.or needs more expensive hardware for the same performance. Along comes the new DBA, sees that the company has database servers running multiple instances (very bad) and suggests to consolidate them into a single instance to simplify management.and the developers tell him it can't be done because every single application has a table named users, a table named logging, a table named configuration, all competing for the same public namespace. They decide they don't like to prefix their tables and just create public synonyms for everything (bad). In this case: developers use several schemas for an application (good). Remember "GOTO considered harmful"? It's not called "GOTO considered inappropriate except in very special cases". If a feature is abused far more often than used, you have every right to declare it "evil" if only tounge in cheek. They make trojan horses all too possible and as importantly they flood the namespace - making consolidation of many developed applications impossible. Public synonyms are another 'feature' I wish we didn't have. I'll let an application have at most one public synonym, if any. If I said "altering current schema at logon avoids having public synonyms or private synonyms in your login schema pointing to your object-owning schema" that begs the question "well, why not use synonyms" - so to short circuit that, I define them as evil. I would rather them avoid - even perhaps be afraid of - synonyms and triggers than think they are an OK approach in general as well. People skim, scan, do whatever - find the answer on the internet, quick. Not enough said in my opinion, not in the year 2009 anyway.
should be avoided, especially by those that cannot figure out when they would not be evil (I'm specifically saying you are *not* in that category). Public synonyms like triggers, autonomous transactions, when others then null. I hope they won't (assume they are tongue in cheek).
0 kommentar(er)
